Washington, Feb 29: Donald Trump and Hillary Clinton are poised to lead America's two major parties in the 2016 presidential election, with a new nationwide poll released on Monday, Feb 29 finding each well ahead of their closest rivals on the eve of the 'Super Tuesday' showdown.

Trump has expanded his lead over the diminished field to capture the support of nearly half of Republican voters, while Clinton tops Bernie Sanders by nearly 20 points on the Democrat votes, according to a CNN/ORC poll.

On the Republican side, the new survey finds Trump's lead is dominant, and his support tops that of his four remaining opponents combined. The 69-year-old real estate tycoon tops his nearest competitor by more than 30 points: 49 per cent back Trump, 16 per cent Marco Rubio, 15 per cent Ted Cruz, 10 per cent Ben Carson and 6 per cent John Kasich.

Trump's supporters are incredibly enthusiastic about the coming election, and largely committed in their support for him. Nearly 8 in 10 say that they are more enthusiastic about voting this year than in previous elections.

Likewise, 78 per cent of Trump's backers say they will definitely support him versus 22 per cent who say they could still change their minds.

The survey asked those Republicans not currently backing Trump whether they would support him if he became the party's nominee, and just a quarter of Republicans overall say they probably or definitely wouldn't support him in November. That is about the same as the share saying they would not back Rubio or Cruz, CNN reported.

Trump is widely viewed as the candidate in the field who would be most effective at solving the country's problems, 51 per cent vs. 17 per cent for Cruz, 13 per cent for Rubio and 10 per cent for Carson.

As accusations of dishonesty have flown between Trump, Cruz and Rubio, voters say they are more apt to see Trump as honest and trustworthy. Asked who of the five candidates is most honest and trustworthy, 35 per cent name Trump, 22 per cent Carson, 14 per cent Cruz and 13 per cent Rubio.

The 'Super Tuesday' on March 1 is the biggest day of the 2016 US presidential primary primary season, with 12 states and one territory participating: Alabama, Arkansas, Colorado, Georgia, Massachusetts, Minnesota, Oklahoma, Tennessee, Texas, Vermont, Virginia, Wyoming and American Samoa.

On the Democratic side, Hillary Clinton tops Bernie Sanders 55 per cent to 38 per cent in the new poll, a slightly wider margin than she held in late January before any primaries or caucuses were held, the report said.

There are sharper demographic splits among the Democratic electorate than on the Republican side.

Men, younger voters, independents and liberals are all about evenly split between 68-year-old Clinton and Sanders, while Clinton's lead rests on large advantages among women, older voters, Democrats and moderates, the report said.